Apparatus and methods for filter bypass for radio frequency front-ends

ABSTRACT

Apparatus and methods for filter bypass for radio frequency front-ends are provided. In certain configurations, a front-end system includes a low noise amplifier, a blocker filter, a plurality of switches configured to control connectivity of the blocker filter and the low noise amplifier in a signal path through the front-end system. The front-end system further includes a controller configured to control the plurality of switches to operate the front-end system in a selected mode chosen from a plurality of modes. The plurality of modes includes a first mode in which the blocker filter is before the low noise amplifier in the signal path, and a second mode in which the low noise amplifier is before the blocker filter in the signal path.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.15/671,997, filed Aug. 8, 2017, and titled “APPARATUS AND METHODS FORFILTER BYPASS FOR RADIO FREQUENCY FRONT-ENDS,” which claims the benefitof priority under 35 U.S.C. § 119(e) of U.S. Provisional PatentApplication No. 62/394,869, filed Sep. 15, 2016 and titled “APPARATUSAND METHODS FOR FILTER BYPASS FOR RADIO FREQUENCY FRONT-ENDS,” and ofU.S. Provisional Patent Application No. 62/373,256, filed Aug. 10, 2016and titled “APPARATUS AND METHODS FOR FILTER BYPASS FOR RADIO FREQUENCYFRONT-ENDS,” each of which is herein incorporated by reference in theirentireties.

BACKGROUND Field

Embodiments of the invention relate to electronic systems, and inparticular, to radio frequency electronics.

Description of Related Technology

Radio frequency (RF) communication systems can be used for transmittingand/or receiving signals of a wide range of frequencies. For example, anRF communication system can be used to wirelessly communicate RF signalsin a frequency range of about 30 kHz to 300 GHz, such as in the range ofabout 450 MHz to about 6 GHz for certain communications standards.

Examples of RF communication systems include, but are not limited to,mobile phones, tablets, base stations, network access points,customer-premises equipment (CPE), laptops, and wearable electronics.

SUMMARY

In certain embodiments, the present disclosure relates to a mobiledevice. The mobile device includes an antenna, a front-end systemconfigured to generate a radio frequency signal based on processing areceived signal from the antenna, and a transceiver configured toreceive the radio frequency signal and to operate the front-end systemin a selected mode chosen from a plurality of modes. The front-endsystem includes one or more filters for providing blocker filtering, andthe transceiver is further configured to change an amount of blockerfiltering provided by the front-end system based on the selected mode.

In some embodiments, the plurality of modes includes a plurality ofautomatic gain control modes.

In various embodiments, the transceiver includes a blocker detectorconfigured to detect a blocker signal level based from the radiofrequency signal, and the transceiver is further configured to choosethe selected mode based on the detected blocker signal level.

In a number of embodiments, the front-end system includes a receivebypass path configured to bypass the one or more filters, and thetransceiver is further configured to select the receive bypass path inat least one of the plurality of modes.

According to some embodiments, the one or more filters includes at leastone tunable filter, and the transceiver is further configured to tunethe at least one tunable filter based on the selected mode.

In several embodiments, the front-end system includes a low noiseamplifier.

In accordance with various embodiments, the transceiver is furtherconfigured to change at least one of a bias or a gain of the low noiseamplifier based on the selected mode.

In a number of embodiments, the transceiver is further configured tobypass the low noise amplifier in at least one of the plurality ofmodes.

In various embodiments, the low noise amplifier includes two or morestages arranged in a cascade, and the transceiver is further configuredto bypass at least one of the two or more stages in at least one of theplurality of modes.

In some embodiments, the transceiver is further configured to change anorder in a signal path of the low noise amplifier and at least one ofthe one or more filters based on the selected mode.

According to a number of embodiments, the one or more filters includes afirst filter before the low noise amplifier in a signal path and asecond filter after the low noise amplifier in the signal path. Invarious embodiments, the transceiver is further configured to bypass atleast one of the first filter or the second filter in at least one ofthe plurality of modes.

In some embodiments, the transceiver includes an automatic gain controlsystem configured to choose the selected mode.

In several embodiments, the automatic gain control system includes atable of gain settings, and one or more gain settings of the tableindicate activation of a receive bypass path that bypasses the one ormore filters.

In various embodiments, the selected mode is controllable over a serialinterface. In a number of embodiments, the serial interface is a MobileIndustry Processor Interface (MIPI) bus.

In accordance with a number of embodiments, the one or more filtersincludes a plurality of receive band filters associated with two or morefrequency bands.

In some embodiments, the front-end system is implemented using timedivision duplexing.

In several embodiments, the front-end system is implemented usingfrequency division duplexing.

In certain embodiments, the present disclosure relates to a front-endsystem for a radio frequency communication device. The front-end systemincludes one or more filters for providing blocker filtering of a signalreceived by an antenna, a plurality of switches configured to controlconnectivity of the one or more filters, and a controller configured tocontrol the plurality of switches to operate the front-end system in aselected mode chosen from a plurality of modes, and to change an amountof blocker filtering provided by the one or more filters based on theselected mode.

In some embodiments, the plurality of modes includes a plurality ofautomatic gain control modes.

In various embodiments, the front-end system further includes a receivebypass path configured to bypass the one or more filters, and thecontroller is further configured to select the receive bypass path in atleast one of the plurality of modes.

In a number of embodiments, the one or more filters includes at leastone tunable filter, and the controller is further configured to tune theat least one tunable filter based on the selected mode.

In several embodiments, the front-end system further includes a lownoise amplifier.

According to various embodiments, the controller is further configuredto change at least one of a bias or a gain of the low noise amplifierbased on the selected mode.

In some embodiments, the controller is further configured to bypass thelow noise amplifier in at least one of the plurality of modes.

In a number of embodiments, the low noise amplifier includes two or morestages arranged in a cascade, and the controller is further configuredto bypass at least one of the two or more stages in at least one of theplurality of modes.

In several embodiments, the controller is further configured to changean order in a signal path of the low noise amplifier and at least one ofthe one or more filters based on the selected mode.

In various embodiments, the one or more filters includes a first filterbefore the low noise amplifier in a signal path and a second amplifierafter the low noise amplifier in the signal path. According to someembodiments, the controller is further configured to bypass at least oneof the first filter or the second filter in at least one of theplurality of modes.

In a number of embodiments, the controller is controllable over a serialinterface. In various embodiments, the serial interface is a MIPI bus.

According to several embodiments, the one or more filters includes aplurality of receive band filters associated with two or more frequencybands.

In some embodiments, the front-end system is implemented using timedivision duplexing.

In accordance with various embodiments, the front-end system isimplemented using frequency division duplexing.

In certain embodiments, the present disclosure relates to a method ofreceiving signals in user equipment of a wireless communication network.The method includes providing a received signal from an antenna to afront-end system that includes one or more filters for providing blockerfiltering, generating a radio frequency signal based on the receivedsignal using the front-end system, operating the front-end system in aselected mode chosen from a plurality of modes, and changing an amountof blocker filtering provided by the front-end system based on theselected mode.

In some embodiments, the method further includes detecting a blockersignal level of the antenna, and choosing the selected mode based on thedetected blocker signal level.

In a number of embodiments, the method further includes bypassing theone or more filters using a receive bypass path in at least one of theplurality of modes.

In various embodiments, the one or more filters includes at least onetunable filter, and the method further includes tuning the at least onetunable filter based on the selected mode.

In several embodiments, generating the radio frequency signal includesproviding amplification using a low noise amplifier in one or more ofthe plurality of modes.

In several embodiments, the method further includes controlling at leastone of a bias or a gain of the low noise amplifier based on the selectedmode.

In some embodiments, the method further includes bypassing the low noiseamplifier in at least one of the plurality of modes.

In a number of embodiments, the low noise amplifier includes two or morestages arranged in a cascade, and the method further includes bypassingat least one of the two or more stages in at least one of the pluralityof modes.

In various embodiments, the method further includes changing an order ina signal path of the low noise amplifier and a filter in at least one ofthe plurality of modes.

According to several embodiments, the method further includes choosingthe selected mode via a serial interface.

In certain embodiments, the present disclosure relates to a radiofrequency communication system includes a baseband processor, a transmitchain configured to process transmit data from the baseband processor togenerate a radio frequency transmit signal, a receive chain configuredto process a radio frequency receive signal to generate receive data forthe baseband processor, one or more antennas, and a front-end systemconfigured to control access of the transmit chain and the receive chainto the one or more antennas. The front-end system including one or morefilters for providing blocker filtering and at least one bypass path forbypassing the one or more filters.

In a number of embodiments, the at least one bypass path includes areceive bypass path operable to couple the receive chain to an antennain a signal path that bypasses the one or more filters.

In some embodiments, the baseband processor includes an automatic gaincontrol system configured to control activation of the receive bypasspath. In various embodiments, the automatic gain control system includesa table of gain settings, the table having one or more gain settingsindicating activation of the receive bypass path.

In varying embodiments, the at least one bypass path includes a transmitbypass path operable to couple the transmit chain to an antenna in asignal path that bypasses the one or more filters.

In several embodiments, the front-end system is implemented using timedivision duplexing.

In a number of embodiments, the front-end system is implemented usingfrequency division duplexing.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram of one embodiment of an RF communicationsystem.

FIG. 2 is a schematic diagram of a receiver system according to oneembodiment.

FIG. 3 is a schematic diagram of one embodiment of an RF front-endsystem operating with time division duplexing (TDD).

FIG. 4 is a schematic diagram of one embodiment of an RF front-endsystem operating with frequency division duplexing (FDD).

FIG. 5 is a schematic diagram of a receiver front-end system accordingto another embodiment.

FIG. 6 is a schematic diagram of a receiver front-end system accordingto another embodiment.

FIG. 7 is a schematic diagram of a receiver front-end system accordingto another embodiment.

FIG. 8 is a schematic diagram of a receiver system according to anotherembodiment.

FIG. 9 is a schematic diagram of a receiver front-end system accordingto another embodiment.

FIG. 10 is a schematic diagram of a receiver front-end system accordingto another embodiment.

FIG. 11 is a schematic diagram of a receiver front-end system accordingto another embodiment.

FIG. 12 is a schematic diagram of a receiver front-end system accordingto another embodiment.

FIG. 13 is a schematic diagram of a receiver front-end system accordingto another embodiment.

FIG. 14 is a schematic diagram of a receiver front-end system accordingto another embodiment.

FIG. 15 is a schematic diagram of a receiver front-end system accordingto another embodiment.

FIG. 16 is a schematic diagram of one embodiment of a mobile device.

FIG. 17A is a schematic diagram of one embodiment of a packaged module.

FIG. 17B is a schematic diagram of a cross-section of the packagedmodule of FIG. 17A taken along the lines 17B-17B.

DETAILED DESCRIPTION OF EMBODIMENTS

The following detailed description of certain embodiments presentsvarious descriptions of specific embodiments. However, the innovationsdescribed herein can be embodied in a multitude of different ways, forexample, as defined and covered by the claims. In this description,reference is made to the drawings where like reference numerals canindicate identical or functionally similar elements. It will beunderstood that elements illustrated in the figures are not necessarilydrawn to scale. Moreover, it will be understood that certain embodimentscan include more elements than illustrated in a drawing and/or a subsetof the elements illustrated in a drawing. Further, some embodiments canincorporate any suitable combination of features from two or moredrawings.

A front-end radio architecture can use filtering for attenuation oftransmit emissions and/or attenuation of out-of-band interferers. Suchfiltering can be provided for coexistence considerations either in-phoneor between user equipment (UE) and external radio environments.

Including such filters achieves desired performance specifications,including in worst-case coexistence conditions. However, such filtersalso introduce insertion loss in the active pass band, for instance,insertion loss in the range of 1 dB to 3 dB. Such insertion loss resultsin a power amplifier in a transmit chain operating with higher outputpower. Additionally, such insertion loss degrades receive sensitivity inreceivers.

Although filter insertion loss undesirably degrades important transmitand receive performance specifications, such filters are used to obtaindesired coexistence performance.

As the interference environment and desired signal levels change,automatic gain control (AGC) in both transmit and receive paths can beutilized. AGC can include changing the gain of active components oftransmit and/or receive chains to adjust gain and linearity dynamicallyto enhance transmission and/or reception performance.

However, filters in both transmit and receive chains support worst-casecoexistence specifications, and penalize the primary passband operation,typically after the power amplifier in the transmit chain, and beforethe low noise amplifier (LNA) in the receive chain.

In certain configurations herein, filter connectivity is changed as afunction of automatic gain control (AGC) in a receive path. For example,lossy filtering can be bypassed when signal conditions and theinterference environment surrounding the UE allow. In certainimplementations, an additional gain state is added to the AGC in theform of a bypass of the filtering. Thus, receiver gain and noise figureare greatly improved while the linearity and susceptibility to blockersis degraded.

Dynamic assessment of the radio environment may allow such operations,and if interferers arise that degrade the receiver performance, then theAGC system can switch the filter back into the receive path. A receiveenvironment can be detected in a variety of ways, such as via a receivedsignal strength indicator (RSSI) or other indication of signal-to-noiseratio (SNR), via processing in a diversity path, via a dedicated blockerdetection chain, and/or in any other suitable way.

Thus, AGC can be extended to include a gain state that providesfilter-less reception of signals. Similar to other gain states of thereceive AGC, desired signal conditions can be used to control theselected gain setting to manage in-band gain and linearity.Additionally, when external interference degrades in-band SNR, the AGCsystem can include the filter in the receive path as needed.Furthermore, as the filters before and/or after a receiver LNA areswitched in or out an assessment can be made to provide an enhancedreceive sensitivity.

On the transmit side, assessment of the received signal as well as thesurrounding UEs that may be affected can be assessed to determine if theadditional transmit emissions are acceptable to the link and to thesurrounding UE and general network performance. Thus, a transmit filtercan be selectively bypassed to reduce transmit path insertion loss,while increasing spurious and/or harmonic transmissions.

Adjustment of the transmit in-band power can be made along withadditional information that the network has for the surrounding UEs andpotential victims of higher emission levels nearby. If configurations inwhich the system/network is sufficiently sophisticated to assess whetheror not a relaxed environment is acceptable, significant benefit for thetransmit output power and DC consumption can also be gained.

The teachings herein can provide enhanced performance in a wide varietyof networks, including, but not limited to, networks using small cellsand/or highly directional short range communication. For example, 5Gsystems can operate using very small network cells and multiple-inputmultiple-output (MIMO) systems operating with beamforming. In suchimplementations, there is a relatively high statistical likelihood thata particular user is isolated from other users of the network. Thus,users of such a network can operate using transmit and/or receive bypassa relatively large percentage of the time, which in turn leads toincreased network performance.

The teachings herein are applicable to both TDD and FDD systems.

For example, a TDD system can include a bypass of a sharedtransmit/receive filter. Additionally, since transmission and receptionoccur sequentially, the shared transmit/receive filter can be bypassedfor both transmit and receive, for transmit but not receive, for receivebut not transmit, or for neither transmit nor receive. Thus, thereconfiguration of transmit and receive bypass can be managedseparately.

In certain implementations, an FDD system is implemented to provideseparate control over transmit and receive bypass. In one example,separate transmit and receive antennas can be used for FDDcommunications via a simplex architecture. In another example, acirculator is used to connect transmit and receive circuitry to a commonantenna. In yet another example, low loss diplex filtering is used inwhich transmit and receive within a band group are kept separate andcombined with different band group frequencies through the diplexfunction before reaching connection to the antenna.

FIG. 1 is a schematic diagram of one embodiment of an RF communicationsystem 20. The RF communication system 20 includes a front-end 1, anantenna 2, a receiver chain 3, a transmitter chain 4, and a basebandprocessor 5. As shown in FIG. 1, the front-end 1 includes filters 10, areceive filter bypass 11, and a transmit filter bypass 12.

The RF communication system 20 of FIG. 1 illustrates one example of a RFcommunication system that can include one or more filter bypass paths.However, the teachings herein are applicable to RF communication systemsimplemented in a wide variety of ways.

When the RF communication system 20 is operating in certainenvironments, the RF communication system 20 can enable the receivefilter bypass 11 to bypass the filters 10. By bypassing the filters 10,received signal strength can be enhanced.

By increasing received signal strength, the RF communication system 20can receive signals from greater distances. Additionally, an increase insignal strength leads to a higher SNR, which in turn permits lowerredundancy and higher data rates or speeds.

For example, an increase in received signal strength can result in achange of encoding format, for instance from QPSK to 16-QAM, therebyproviding less redundancy and higher bit rate. A change in receivedsignal strength can further impact performance via changes to operationof diversity and/or MIMO.

Additionally, the RF communication system 20 can operate with enhancedperformance specifications, such as superior reference sensitivity. Aspersons having ordinary skill in the art will appreciate, a referencesensitivity test can measure a communication system's performance withrespect to processing received signals of relatively low signalstrength.

When the RF communication system 20 is operating in certainenvironments, the RF communication system 20 can enable the transmitfilter bypass 12 to bypass the filters 10. By bypassing the filters 10,transmit power can be decreased, since a transmit signal form thetransmit chain 4 can reach the antenna 2 without the insertion loss ofthe filters 10.

Decreasing transmit power can enhance performance, including extendingbattery life and/or reducing heat dissipation in the RF communicationsystem 20.

Although illustrated with respect to a single antenna, the teachingsherein are applicable to multi-antenna configurations. In one example,multiple antennas are used for FDD. In another example, a diversityantenna is used. The diversity antenna and/or other antennas can includetransmit and/or receive bypass paths.

FIG. 2 is a schematic diagram of a receiver system 50 according to oneembodiment.

The receiver system 50 includes an antenna 2, a front-end 21, a receiverchain 22, and a baseband processor 25. The front-end 21 includes filters30 and a receive filter bypass 31. Additionally, the receiver chain 22includes an LNA 41, an I/Q demodulator 42, an I-path variable gainamplifier (VGA) 43 a, a Q-path VGA 43 b, an I-path analog-to-digitalconverter (ADC) 44 a, and a Q-path ADC 44 b. The baseband processor 25includes an AGC system 35.

The AGC system 35 can adjust gain of components in the receiver chain 22in order to achieve an in-band component of the received signal at adesired strength. The AGC system 35 can provide gain control thatpositions the received input signal in about the middle of a dynamicrange of the ADCs 44 a, 44 b. Providing gain control in this manner aidsin generating a received signal of an appropriate level, and enhancesthe integrity of signal reception in the receiver system 50.

In the illustrated example, the AGC system 35 generates gain controlssignals for the LNA 41, the I/Q demodulator 42 (for instance, mixer gaincontrol), and the VGAs 43 a, 43 b. However, other implementations ofgain control are possible.

The digital I signal and the digital Q signal from the I-path ADC 44 aand the Q-path ADC 44 b, respectively, can be processed by the basebandprocessor 25 to determine an RSSI. The RSSI can be used by the AGCsystem 35 to select an appropriate gain state associated with particulargain settings of one or more gain controls signals.

The RSSI indicates a quality index of received signals, and can becompared to an expected signal strength level. When the RSSI isrelatively low, the AGC system 35 can change the AGC state to increasethe gain. For instance, the AGC system 35 can include a receiver AGCtable of AGC states, and can change the AGC state from one state toanother based on the RSSI. Thus, the AGC system 35 can change AGC stateuntil RSSI has a desired value or is within a range of desired values.

In certain configurations, the receive filter bypass 31 is activated inone or more AGC settings or states. In one embodiment, the receivefilter bypass 31 is activated in a highest gain setting of the AGCsystem 35, such as a highest gain value in the receiver AGC table. Thus,when received signal strength is relatively weak, the AGC system 35 canbypass the front-end's filters to receive the signal without theattenuation of the filters. When the RSSI increases in response tobypassing the filters, signal integrity is enhanced. However, when theRSSI decreases in response to bypassing the filters, the AGC system 35can back out of the bypass state.

The illustrated receiver system 50 can exhibit superior performance in areference sensitivity test. For example, as signal strength decreasesduring the reference sensitivity test, the AGC system 35 can increasegain of the receive chain 22. Additionally, as the signal strength isrelatively weak and receive chain 22 is operating with a maximum gainlevel, the AGC system 35 can bypass the front-end's filters, therebyincreasing signal strength by avoiding filter insertion loss.

Accordingly, the receiver system 50 can detect signals of smallerstrength, and exhibit superior performance specifications with respectto reference sensitivity.

The baseband processor 25 can provide digitally channel filtering toremove received signal components associated with blockers and/or otherdesired signal components. Thus, when the receive filter bypass 31 isactivated, digital filtering in the baseband processor 25 can be used torecover a desired signal. Thus, the receiver system 50 can reliablereceive signals even when the filters 30 are bypassed.

FIG. 3 is a schematic diagram of one embodiment of an RF front-endsystem 100 operating with TDD. The RF front-end system 100 is connectedto an antenna 2, and includes a transmit/receive (T/R) switch 101, anantenna switch module (ASM) 103, a power amplifier 105, an LNA 106, afirst band filter 111, a second band filter 112, a third band filter113, and a filter bypass 115.

The RF front-end system 100 of FIG. 3 illustrates one specificembodiment of filter bypass for a system operating with TDD. However, awide variety of bypass architectures can be used, including, forexample, configurations with more or fewer bands, switches, and/or othercomponents.

To receive signals, the LNA 106 is connected to antenna 2 through aselected path between the T/R switch 101 and the ASM 103. Additionally,to transmit signals, the power amplifier 105 is connected to the antenna2 through a selected path between the T/R switch 101 and the ASM 103.The ASM 103 can also be referred to as an antenna switch.

With respect to reception of signals, the filtering provided by the bandfilters 111-113 can reduce blockers down such that an overall linearityis achieved. With respect to transmission of signals, the filteringprovided by the band filters 111-113 can reduce spurious and/orout-of-band transmission.

The band filters 111-113 can be used to attenuate interference,including, but not limited to, interference from transmitters of otherUE and/or from in-phone transmitters. For instance, certain phones caninclude a primary transmitter, such as a cellular transmitter, and anauxiliary transmitter, such as a Wi-Fi transmitter, and the band filters111-113 aid in providing in-phone coexistence.

The illustrated RF front-end system 100 includes the filter bypass 115,which can be used to bypass the band filters 111-113 to providereception and/or transmission of signals without the insertion loss ofthe band filters 111-113.

Although the illustrated filter bypass 115 includes a direct connectionbetween the T/R switch 101 and the ASM 103, other implementations arepossible. For example, the filter bypass 115 can include a filter havinga smaller amount of attenuation relative to the band filters 111-113.Moreover, the teachings herein are applicable to implementations usingmultiple bypass paths, including, but not limited to, bypass pathshaving filters of varying strengths.

The illustrated RF front-end system 100 operates with TDD, and thustransmission and reception occurs at different time instances, in thisexample. Accordingly, the filter bypass 115 can be selected whentransmitting and receiving, when transmitting but not when receiving,when receiving but not transmitting, or neither when transmitting norreceiving. Moreover, the use of the filter bypass 115 is dynamicallycontrolled over time based on operating environment.

In one embodiment, use of the filter bypass 115 is controlled viacontrols signals from a baseband processor. For example, the basebandprocessor can generate signals that control selection of the T/R switch101 and the ASM 103.

FIG. 4 is a schematic diagram of one embodiment of an RF front-endsystem 120 operating with FDD.

The RF front-end system 120 is connected to a transmit antenna 2 a and areceive antenna 2 b, and includes a power amplifier 105, an LNA 106, atransmit switch 121, a receive switch 122, a first ASM 123, a second ASM124, a first transmit band filter 131, a second transmit band filter132, a transmit filter bypass 135, a first receive band filter 141, asecond receive filter 142, and a receive filter bypass 145.

The RF front-end system 120 of FIG. 4 illustrates one specificembodiment of filter bypass for a system operating with FDD. However, awide variety of bypass architectures can be used, including, forexample, configurations with more or fewer bands, switches, and/or othercomponents.

In the illustrated embodiment, a simplex architecture with separatetransmit and receive antennas is used. However, other implementationsare possible. For example, a single antenna can be used in combinationwith a circulator or low loss duplexer.

FIG. 5 is a schematic diagram of a receiver front-end system 300according to another embodiment. The receiver front-end system 300includes an LNA bypass switch 301, a filter bypass switch 302, anantenna switch 303, an LNA 306, and a receive band filter 311.

In the illustrated embodiment, the antenna switch 303 selectively routesa received signal 321 to an input of the receive band filter 311 forfiltering, to the receive filter bypass 315, or to the LNA bypass 316.Additionally, the filter bypass switch 302 selectively routes an outputof the receive band filter 311 or the receive filter bypass 315 to aninput of the LNA 306. Furthermore, the LNA bypass switch 301 selects anoutput of the LNA 306 or the LNA bypass 316 to provide as an outputsignal 322.

Accordingly, in this example, the receive filter bypass 315 can be usedto bypass the receive band filter 311 but not the LNA 306, and the LNAbypass 316 can be used to bypass both the receive band filter 311 andthe LNA 306. Implementing the receiver front-end system 300 in thismanner enhances flexibility in controlling an amount of filtering andamplification provided to the received signal 321.

Although FIG. 5 illustrates one specific embodiment of filter and LNAbypass, a wide variety of bypass architectures can be used, including,for example, configurations with additional filters, switches, and/orother components and/or a different arrangement of components.

FIG. 6 is a schematic diagram of a receiver front-end system 350according to another embodiment. The receiver front-end system 350includes a bypass switch 351, an antenna switch 353, a receive bandfilter 361, a first LNA 356 a, and a second LNA 356 b. The receiverfront-end system 350 receives a receive signal 371 and generates anoutput signal 372.

In the illustrated embodiment, the bypass switch 351 and the antennaswitch 353 can operate to select a first path associated with thereceive band filter 361 and the first LNA 356 a, a second pathassociated with the second LNA 356 b and the filter bypass 365, or athird path associated with the LNA bypass 316.

Accordingly, in this example, the receive filter bypass 365 can be usedto bypass the receive band filter 311 and the first LNA 356 a but notthe second LNA 356 b, and the LNA bypass 366 can be used to bypass thereceive band filter 311 and the first and second LNAs 356 a, 356 b.Implementing the receiver front-end system 300 in this manner enhancesflexibility in controlling an amount of filtering and amplificationprovided to the received signal 371. For example, the first pathprovides both filtering by the receive band filter 361 and amplificationby the first LNA 356 a, the second path provides amplification by thesecond LNA 356 b, and the third path bypasses filter and LNA circuitry.The first and second LNAs 356 a, 356 b can provide the same or differentamounts of amplification, based on implementation.

Although FIG. 6 illustrates one specific embodiment of filter and LNAbypass, a wide variety of bypass architectures can be used, including,for example, configurations with additional filters, switches, and/orother components and/or a different arrangement of components.

FIG. 7 is a schematic diagram of a receiver front-end system 450according to another embodiment. The receiver front-end system 450includes a first crosspoint switch 451, a second crosspoint switch 452,a receive band filter 461, and an LNA 456. The receiver front-end system450 receives a receive signal 471 and generates an output signal 472.

As shown in FIG. 7, the schematic diagram has also been annotated toshow a filter first receive system 400 including a cascade of a firstswitch component 401, a receive band filter 411, a second switchcomponent 402, an LNA 406, and a third switch component 403.Additionally, the schematic diagram has been annotated to show an LNAfirst receive system 410 including a cascade of the first switchcomponent 401, the LNA 406, the second switch component 402, the receiveband filter 411, and the third switch component 403. Both the filterfirst receive system 400 and the LNA first receive system 410 process areceive signal 421 to generate an output signal 422, but include adifferent order of the receive band filter 411 and the LNA 406 incascade.

The receiver front-end system 450 includes first and second cross-pointswitches 451, 452, which can be used to implemented a filter firstreceive system, an LNA first receive system, as well as to bypass thereceive band filter 461 or the LNA 456.

For example, in a filter first configuration, the first cross-pointswitch 451 can provide the receive signal 471 to an input of the receiveband filter 461, and the second cross-point switch 452 can connect anoutput of the receive band filter 461 to the first cross-point switch451 via a loopback path 475. Additionally, the first cross-point switch451 can connect the loopback path 475 to an input of the LNA 456, andthe second cross-point switch 452 can provide the output signal 472 byselecting an output of the LNA 456.

Additionally, in an LNA first configuration, the first cross-pointswitch 451 can provide the receive signal 471 to the input of the LNA456, and the second cross-point switch 452 can connect the output of theLNA 456 to the first cross-point switch 451 via the loopback path 475.Additionally, the first cross-point switch 451 can connect the loopbackpath 475 to the input of the receive band filter 461, and the secondcross-point switch 452 can provide the output signal 472 by selectingthe output of the receive band filter 461.

Furthermore, in a filter bypass configuration, the first cross-pointswitch 451 can provide the receive signal 471 to the input of the LNA456, and the second cross-point switch 452 can provide the output signal472 by selecting the output of the LNA 456.

Additionally, in an LNA bypass configuration, the first cross-pointswitch 451 can provide the receive signal 471 to the input of thereceive band filter 461, and the second cross-point switch 472 canprovide the output signal 452 by selecting the output of the receiveband filter 461.

Implementing the receiver front-end system 450 in this manner enhancesflexibility in controlling an amount of filtering and amplificationprovided to the received signal 471, including control over an order ofan LNA and a receive band filter in a cascade.

Although FIG. 7 illustrates one specific embodiment of filter and LNAbypass, a wide variety of bypass architectures can be used, including,for example, configurations with additional filters, switches, and/orother components and/or a different arrangement of components.

FIG. 8 is a schematic diagram of a receiver system 600 according toanother embodiment. The receiver system 600 includes a transceiver 601,receiver front-end circuitry 602, and an antenna 603. The illustratedreceiver front-end circuitry 602 includes an antenna switch 611, abypass switch 612, a receive control circuit 614, a first LNA 621, asecond LNA 622, and a receive band filter 625. Additionally, theillustrated transceiver 601 includes an amplifier 641, a mixer 642, ablocker detector 645, and a controller 650.

Although not illustrated in FIG. 8 for clarity, the transceiver 601 caninclude circuitry associated with transmitting signals over one or moretransmit paths and/or one or more additional receive paths. Furthermore,the receiver system 600 can further include a baseband processor and/orother components for processing transmit and receive signals.

The antenna switch 611 and the bypass switch 612 can be used to select afirst receive path 631 with blocker filtering or a second receive path632 without blocker filtering. As shown in FIG. 8, the illustratedembodiment includes a first LNA 621 in the first receive path 631 and asecond LNA 622 in the second receive path 632. The first and second LNAs621, 622 can have the same or different amplification characteristics,depending on implementation and/or application.

As shown in FIG. 8, the output signal from the receiver front-endcircuitry 602 is amplified by the transceiver's amplifier 641, anddown-converted by the mixer 642. The blocker detector 645 senses anoutput of the mixer 642 (for instance, via a directional coupler 643),and provides a blocker detection signal to the transceiver's controller650. The controller 650 includes a gain/bias control circuit 651 and apath select circuit 652 that processes the blocker detection signal toselect an appropriate mode or setting for automatic gain control of thereceiver front-end circuitry 600.

The transceiver's controller 650 provides a gain/bias control signal anda path select control signal to the receive control circuit 614 of thereceiver front-end circuitry 602. In illustrated embodiment, thegain/bias control signal and a path select control signal are providedvia a serial interface 660, such as a Mobile Industry ProcessorInterface (MIPI) bus. The receive control circuit 614 controls theantenna switch 611 and the bypass switch 612 based on the path selectcontrol signal, and controls gain and bias settings of the first andsecond LNAs 621, 622 based on the gain/bias control signal.

Accordingly, the receive filtering and amplification characteristics canbe controlled by the transceiver 601, including based on a detectedblocker level.

Accordingly, the receiver system 600 of FIG. 8 illustrates an embodimentin which filter connectivity is changed as a function of AGC. Forexample, the transceiver's controller 651 includes a gain state thatprovides filter-less reception of signals. Thus, lossy filtering of thereceive band filter 625 can be bypassed when signal conditions and theinterference environment permit. The blocker level is detected via theblocker detector 645, in this embodiment, thereby allowing receiver gainand noise figure to be improved when blocker levels are low.

Additionally, the receiver system 600 can operate with differentgain/bias tunings for different modes. In one example, a receive pathwith filter bypass and low current settings can be provided in one mode,while a different receive path with filtering and high current settingscan be provided in another mode.

FIG. 9 is a schematic diagram of a receiver front-end system 700according to another embodiment. The receiver front-end system 700 isconnected to an antenna 702, and includes a first switch 711, a secondswitch 712, a third switch 713, a fourth switch 714, a pre-LNA receiveband filter 721, an LNA 725, and a post-LNA receive band filter 722.

As shown in FIG. 9, the pre-LNA receive band filter 721 can beselectively bypassed via a first filter bypass 731 and/or the post-LNAreceive band filter 722 can be selectively bypassed via a second filterbypass 732.

The illustrated embodiment illustrates one example of a receiverfront-end system that includes distributed receive band filters that canbe selectively bypassed. However, the teachings herein are applicable toa wide variety of bypass architectures, including, for example,configurations with additional filters, switches, and/or othercomponents and/or a different arrangement of components.

FIG. 10 is a schematic diagram of a receiver front-end system 740according to another embodiment. The receiver front-end system 740 isconnected to an antenna 702, and includes a first switch 741, a secondswitch 712, a third switch 713, a fourth switch 744, a pre-LNA receiveband filter 721, an LNA 725, and a post-LNA receive band filter 722.

The receiver front-end system 740 of FIG. 10 is similar to the receiverfront-end system 700 of FIG. 9, except that the receiver front-endsystem 740 is implemented with a filter and LNA bypass 733 that isselectable by the first switch 741 and the fourth switch 744. The filterand LNA bypass 733 allows bypassing of the pre-LNA receive band filter721, the LNA 725, and the post-LNA receive band filter 722.

Additional details of the receiver front-end system 740 can be similarto those described earlier.

FIG. 11 is a schematic diagram of a receiver front-end system 750according to another embodiment. The receiver front-end system 750 isconnected to an antenna 702, a first transceiver 761, and a secondtransceiver 762. Additionally, the receiver front-end system 750includes a first switch 741, a second switch 712, a third switch 713, afourth switch 754, a pre-LNA receive band filter 721, an LNA 725, apost-LNA receive band filter 722, and a routing circuit 765.

The receiver front-end system 750 of FIG. 11 is similar to the receiverfront-end system 740 of FIG. 10, except that the receiver front-endsystem 750 further includes the routing circuit 765 for connecting tothe first transceiver 761 and the second transceiver 762. The fourthswitch 754 and the routing circuit 765 operate to selectively connectthe first transceiver 761 or the second transceiver 762 to the antenna702 via a desired receive path. Including the routing circuit 765enhances flexibility of the receiver front-end system and permitssharing of circuitry amongst multiple transceivers.

Additional details of the receiver front-end system 750 can be similarto those described earlier.

FIG. 12 is a schematic diagram of a receiver front-end system 770according to another embodiment. The receiver front-end system 770 isconnected to an antenna 702, a first transceiver 761, and a secondtransceiver 762. Additionally, the receiver front-end system 770includes an antenna 702, a first switch 741, a second switch 712, athird switch 713, a fourth switch 754, a fifth switch 771, a sixthswitch 772, a pre-LNA receive band filter 721, a first LNA stage 775, asecond LNA stage 776, a post-LNA receive band filter 722, and a routingcircuit 765.

The receiver front-end system 770 of FIG. 12 is similar to the receiverfront-end system 750 of FIG. 11, except that the receiver front-endsystem 770 includes an LNA implemented in multiple stages 775, 776.Additionally, the receiver front-end system 770 includes additionalswitches to bypass the second LNA stage 776 via the LNA bypass 773.

Accordingly, the receiver front-end system 770 of FIG. 12 providesenhanced flexibility in controlling an amount of gain in a selectedreceive path, since the number of active LNA stages in the selectedreceive path can be controlled.

Additional details of the receiver front-end system 770 can be similarto those described earlier.

FIG. 13 is a schematic diagram of a receiver front-end system 800according to another embodiment. The receiver front-end system 800 isconnected to an antenna 802, and includes an LNA 803, a detector 804, aMIPI controller 805, a first filter with bypass circuit 811, and asecond filter with bypass circuit 812.

The first filter with bypass circuit 811 can be used to selectivelyfilter a received signal from the antenna 811. Additionally, an outputof the first filter with bypass circuit 811 is provided to an input ofthe LNA 803. Additionally, an output of the LNA 803 is provided to thesecond filter with bypass circuit 812 and to the detector 804. Thesecond filter with bypass circuit 812 can be used to selectively filterthe output of the LNA 803.

The detector 804 processes the output of the LNA 803, and can be used todetect a blocker level or strength at the antenna 802. The detector 804provides a blocker detection signal to the MIPI controller 805, whichcontrols the first filter with bypass circuit 811 and the second filterwith bypass circuit 812. Thus, the MIPI controller 805 can be used toselectively activate one or more bypass circuits to bypass filtering.

Additional details of the receiver front-end system 800 can be asdescribed earlier.

FIG. 14 is a schematic diagram of a receiver front-end system 820according to another embodiment. The receiver front-end system 820includes an antenna 802, an LNA 803, a detector 804, a MIPI controller805, a first filter circuit 821 with a first tunable filter 831, and asecond filter circuit 822 with a second tunable filter 822.

The receiver front-end system 820 of FIG. 14 is similar to the receiverfront-end system 800 of FIG. 13, except that the receiver front-endsystem 820 of FIG. 14 includes a MIPI controller 805 that controls anamount of filtering provided by the first and second tunable filters821, 822 rather than bypassing filters. By controlling the tunablefilters, an amount of filtering of the first filter circuit 821 and/orthe second filter circuit 822 can be reduced. In certainimplementations, the first filter circuit 821 and/or the second filtercircuit 822 can be substantially bypassed by tuning the first tunablefilter 831 and/or the second tunable filter 832 to provide substantiallyno filtering.

Additional details of the receiver front-end system 800 can be asdescribed earlier.

FIG. 15 is a schematic diagram of a receiver front-end system 950according to another embodiment. The receiver front-end system 950includes a first switch 901, a second switch 902, a third switch 903, afourth switch 904, a fifth switch 905, a sixth switch 906, a seventhswitch 907, an LNA 908, and a receive band filter 909. The receiverfront-end system 950 receives a receive signal at an input IN andgenerates an output signal at an output OUT.

As shown in FIG. 15, the schematic diagram has also been annotated toshow the receiver front-end system 950 with different switch selectionsor configurations. By opening or closing a particular combination ofswitches, different combinations of bypassing and signal path orders ofthe LNA 908 and the receive band filter 909 can be achieved.

As shown in a first switch configuration 900, the fifth switch 905, thereceive band filter 909, the seventh switch 907, the LNA 908, and thesecond switch 902 are electrically connected in a cascade between theinput IN and the output OUT. Thus, both the receive band filter 909 andthe LNA 908 are in the signal path in the first switch configuration900, with the receive band filter 909 preceding the LNA 908.

Additionally, in a second switch configuration 910, the fourth switch904, the LNA 908, the sixth switch 906, the receive band filter 909, andthe first switch 901 are electrically connected in a cascade between theinput IN and the output OUT. Thus, both the LNA 908 and the receive bandfilter 909 and are in the signal path in the second switch configuration910, with the LNA 908 preceding the receive band filter 909.

Furthermore, in a third switch configuration 920, the fifth switch 905,the receive band filter 909, and the first switch 901 are electricallyconnected in a cascade between the input IN and the output OUT. Thus,the receive band filter 909 but not the LNA 908 is in the signal path inthe third switch configuration 920.

Additionally, in a fourth switch configuration 930, the fourth switch904, the LNA 908, and the second switch 902 are electrically connectedin a cascade between the input IN and the output OUT. Thus, the LNA 908but not the receive band filter 909 is in the signal path in the fourthswitch configuration 930.

Furthermore, in a fifth switch configuration 940, the third switch 903is between the input IN and the output OUT. Thus, neither the LNA 908nor the receive band filter 909 are in the signal path in the fifthswitch configuration 940.

Thus, the receiver front-end system 950 can be used to implemented afilter first receive system, an LNA first receive system, a filter onlyreceive system, an LNA only receive system, or to bypass both the LNAand the filter.

Although FIG. 15 illustrates one specific embodiment of filter and LNAbypass, a wide variety of bypass architectures can be used, including,for example, configurations with additional filters, switches, and/orother components and/or a different arrangement of components.

FIG. 16 is a schematic diagram of one embodiment of a mobile device1800. The mobile device 1800 includes a baseband system 1801, atransceiver 1802, a front-end system 1803, one or more antennas 1804, apower management system 1805, a memory 1806, a user interface 1807, anda battery 1808.

The mobile device 1800 can be used communicate using a wide variety ofcommunications technologies, including, but not limited to, 2G, 3G, 4G(including LTE, LTE-Advanced, and LTE-Advanced Pro), 5G NR, WLAN (forinstance, Wi-Fi), WPAN (for instance, Bluetooth and ZigBee), WMAN (forinstance, WiMax), and/or GPS technologies.

The transceiver 1802 generates RF signals for transmission and processesincoming RF signals received from the antennas 1804. It will beunderstood that various functionalities associated with the transmissionand receiving of RF signals can be achieved by one or more componentsthat are collectively represented in FIG. 16 as the transceiver 1802. Inone example, separate components (for instance, separate circuits ordies) can be provided for handling certain types of RF signals.

The front-end system 1803 aids is conditioning signals transmitted toand/or received from the antennas 1804. In the illustrated embodiment,the front-end system 1803 includes one or more power amplifiers (PAs)1811, one or more low noise amplifiers (LNAs) 1812, one or more filters1813, one or more switches 1814, and one or more duplexers 1815.However, other implementations are possible.

For example, the front-end system 1803 can provide a number offunctionalities, including, but not limited to, amplifying signals fortransmission, amplifying received signals, filtering signals, switchingbetween different bands, switching between different power modes,switching between transmission and receiving modes, duplexing ofsignals, multiplexing of signals (for instance, diplexing ortriplexing), or some combination thereof.

The front-end system 1803 is implemented using one or more featuresdisclosed herein. For example, filter connectivity of the front-endsystem 1803 is changed as a function of automatic gain control (AGC).Thus lossy filtering of all or part of the filters 1813 can be bypassedwhen signal conditions and the surrounding interference environmentallow.

In certain implementations, the mobile device 1800 supports carrieraggregation, thereby providing flexibility to increase peak data rates.Carrier aggregation can be used for both Frequency Division Duplexing(FDD) and Time Division Duplexing (TDD), and may be used to aggregate aplurality of carriers or channels. Carrier aggregation includescontiguous aggregation, in which contiguous carriers within the sameoperating frequency band are aggregated. Carrier aggregation can also benon-contiguous, and can include carriers separated in frequency within acommon band or in different bands.

The antennas 1804 can include antennas used for a wide variety of typesof communications. For example, the antennas 1804 can include antennasfor transmitting and/or receiving signals associated with a wide varietyof frequencies and communications standards.

In certain implementations, the antennas 1804 support MIMOcommunications and/or switched diversity communications. For example,MIMO communications use multiple antennas for communicating multipledata streams over a single radio frequency channel. MIMO communicationsbenefit from higher signal to noise ratio, improved coding, and/orreduced signal interference due to spatial multiplexing differences ofthe radio environment. Switched diversity refers to communications inwhich a particular antenna is selected for operation at a particulartime. For example, a switch can be used to select a particular antennafrom a group of antennas based on a variety of factors, such as anobserved bit error rate and/or a signal strength indicator.

The mobile device 1800 can operate with beamforming in certainimplementations. For example, the front-end system 1803 can includephase shifters having variable phase controlled by the transceiver 1802.Additionally, the phase shifters are controlled to provide beamformation and directivity for transmission and/or reception of signalsusing the antennas 1804. For example, in the context of signaltransmission, the phases of the transmit signals provided to theantennas 1804 are controlled such that radiated signals from theantennas 1804 combine using constructive and destructive interference togenerate an aggregate transmit signal exhibiting beam-like qualitieswith more signal strength propagating in a given direction. In thecontext of signal reception, the phases are controlled such that moresignal energy is received when the signal is arriving to the antennas1804 from a particular direction. In certain implementations, theantennas 1804 include one or more arrays of antenna elements to enhancebeamforming.

The baseband system 1801 is coupled to the user interface 1807 tofacilitate processing of various user input and output (I/O), such asvoice and data. The baseband system 1801 provides the transceiver 1802with digital representations of transmit signals, which the transceiver1802 processes to generate RF signals for transmission. The basebandsystem 1801 also processes digital representations of received signalsprovided by the transceiver 1802. As shown in FIG. 16, the basebandsystem 1801 is coupled to the memory 1806 of facilitate operation of themobile device 1800.

The memory 1806 can be used for a wide variety of purposes, such asstoring data and/or instructions to facilitate the operation of themobile device 1800 and/or to provide storage of user information.

The power management system 1805 provides a number of power managementfunctions of the mobile device 1800. In certain implementations, thepower management system 1805 includes a PA supply control circuit thatcontrols the supply voltages of the power amplifiers 1811. For example,the power management system 1805 can be configured to change the supplyvoltage(s) provided to one or more of the power amplifiers 1811 toimprove efficiency, such as power added efficiency (PAE).

As shown in FIG. 16, the power management system 1805 receives a batteryvoltage from the battery 1808. The battery 1808 can be any suitablebattery for use in the mobile device 1800, including, for example, alithium-ion battery.

FIG. 17A is a schematic diagram of one embodiment of a packaged module1900. FIG. 17B is a schematic diagram of a cross-section of the packagedmodule 1900 of FIG. 17A taken along the lines 17B-17B.

The packaged module 1900 includes radio frequency components 1901, asemiconductor die 1902, filters 1903, wirebonds 1908, a packagesubstrate 1920, and encapsulation structure 1940. The package substrate1920 includes pads 1906 formed from conductors disposed therein.Additionally, the semiconductor die 1902 includes pins or pads 1904, andthe wirebonds 1908 have been used to connect the pads 1904 of the die1902 to the pads 1906 of the package substrate 1920.

The semiconductor die 1902 includes a receive bypass 1950. The packagedmodule 1900 is implemented using one or more features disclosed herein.For example, one or more of the filters 1903 can be bypassed via the RXbypass 1950 when signal conditions and the surrounding interferenceenvironment allow. Although the packaged module 1900 illustrates oneexample of a module implemented in accordance with the teachings herein,other implementations are possible.

The packaging substrate 1920 can be configured to receive a plurality ofcomponents such as the semiconductor die 1902 and the filters 1903,which can include, for example, surface acoustic wave (SAW) and/or bulkacoustic wave (BAW) filters.

As shown in FIG. 17B, the packaged module 1900 is shown to include aplurality of contact pads 1932 disposed on the side of the packagedmodule 1900 opposite the side used to mount the semiconductor die 1902.Configuring the packaged module 1900 in this manner can aid inconnecting the packaged module 1900 to a circuit board, such as a phoneboard of a wireless device. The example contact pads 1932 can beconfigured to provide radio frequency signals, bias signals, and/orpower (for example, a power supply voltage and ground) to thesemiconductor die 1902. As shown in FIG. 17B, the electrical connectionsbetween the contact pads 1932 and the semiconductor die 1902 can befacilitated by connections 1933 through the package substrate 1920. Theconnections 1933 can represent electrical paths formed through thepackage substrate 1920, such as connections associated with vias andconductors of a multilayer laminated package substrate.

In some embodiments, the packaged module 1900 can also include one ormore packaging structures to, for example, provide protection and/orfacilitate handling.

Such a packaging structure can include overmold or encapsulationstructure 1940 formed over the packaging substrate 1920 and thecomponents and die(s) disposed thereon.

It will be understood that although the packaged module 1900 isdescribed in the context of electrical connections based on wirebonds,one or more features of the present disclosure can also be implementedin other packaging configurations, including, for example, flip-chipconfigurations.

Applications

Some of the embodiments described above have provided examples inconnection with mobile devices. However, the principles and advantagesof the embodiments can be used for any other systems or apparatus thathave needs for filter bypass. Examples of such RF communication systemsinclude, but are not limited to, mobile phones, tablets, base stations,network access points, customer-premises equipment (CPE), laptops, andwearable electronics.

Conclusion

Unless the context clearly requires otherwise, throughout thedescription and the claims, the words “comprise,” “comprising,” and thelike are to be construed in an inclusive sense, as opposed to anexclusive or exhaustive sense; that is to say, in the sense of“including, but not limited to.” The word “coupled”, as generally usedherein, refers to two or more elements that may be either directlyconnected, or connected by way of one or more intermediate elements.Likewise, the word “connected”, as generally used herein, refers to twoor more elements that may be either directly connected, or connected byway of one or more intermediate elements. Additionally, the words“herein,” “above,” “below,” and words of similar import, when used inthis application, shall refer to this application as a whole and not toany particular portions of this application. Where the context permits,words in the above Detailed Description using the singular or pluralnumber may also include the plural or singular number respectively. Theword “or” in reference to a list of two or more items, that word coversall of the following interpretations of the word: any of the items inthe list, all of the items in the list, and any combination of the itemsin the list.

Moreover, conditional language used herein, such as, among others,“can,” “could,” “might,” “can,” “e.g.,” “for example,” “such as” and thelike, unless specifically stated otherwise, or otherwise understoodwithin the context as used, is generally intended to convey that certainembodiments include, while other embodiments do not include, certainfeatures, elements and/or states. Thus, such conditional language is notgenerally intended to imply that features, elements and/or states are inany way required for one or more embodiments or that one or moreembodiments necessarily include logic for deciding, with or withoutauthor input or prompting, whether these features, elements and/orstates are included or are to be performed in any particular embodiment.

The above detailed description of embodiments of the invention is notintended to be exhaustive or to limit the invention to the precise formdisclosed above. While specific embodiments of, and examples for, theinvention are described above for illustrative purposes, variousequivalent modifications are possible within the scope of the invention,as those skilled in the relevant art will recognize. For example, whileprocesses or blocks are presented in a given order, alternativeembodiments may perform routines having steps, or employ systems havingblocks, in a different order, and some processes or blocks may bedeleted, moved, added, subdivided, combined, and/or modified. Each ofthese processes or blocks may be implemented in a variety of differentways. Also, while processes or blocks are at times shown as beingperformed in series, these processes or blocks may instead be performedin parallel, or may be performed at different times.

The teachings of the invention provided herein can be applied to othersystems, not necessarily the system described above. The elements andacts of the various embodiments described above can be combined toprovide further embodiments.

While certain embodiments of the inventions have been described, theseembodiments have been presented by way of example only, and are notintended to limit the scope of the disclosure. Indeed, the novel methodsand systems described herein may be embodied in a variety of otherforms; furthermore, various omissions, substitutions and changes in theform of the methods and systems described herein may be made withoutdeparting from the spirit of the disclosure. The accompanying claims andtheir equivalents are intended to cover such forms or modifications aswould fall within the scope and spirit of the disclosure.

What is claimed is:
 1. A mobile device comprising: an antenna; afront-end system including a blocker filter, a low noise amplifier, anda plurality of switches; and a transceiver configured to receive a radiofrequency signal from the antenna by way of a signal path through thefront-end system, the transceiver configured to control the plurality ofswitches to operate the front-end system in a selected mode chosen froma plurality of modes, including a first mode in which the blocker filteris before the low noise amplifier in the signal path, and a second modein which the low noise amplifier is before the blocker filter in thesignal path.
 2. The mobile device of claim 1 wherein the plurality ofswitches includes a first crosspoint switch and a second crosspointswitch, the low noise amplifier electrically connected between a firstoutput of the first crosspoint switch and a first input of the secondcrosspoint switch, and the blocker filter connected between a secondoutput of the first crosspoint switch and a second input of the secondcrosspoint switch.
 3. The mobile device of claim 2 wherein an output ofthe second crosspoint switch is coupled to an input of the firstcrosspoint switch by a loopback path.
 4. The mobile device of claim 1wherein the plurality of switches includes a first switch connectedbetween an output terminal and an output of the blocker filter, a secondswitch connected between the output terminal and an output of the lownoise amplifier, and a third switch connected between the outputterminal and an input terminal.
 5. The mobile device of claim 4 whereinthe plurality of switches further includes a fourth switch connectedbetween the input terminal and an input to the low noise amplifier, afifth switch connected between the input terminal and an input to theblocker filter, a sixth switched connected between the output of the lownoise amplifier and the input to the blocker filter, and a seventhswitch connected between the input of the low noise amplifier and theoutput of the blocker filter.
 6. The mobile device of claim 1 whereinthe plurality of modes further includes a third mode in which theblocker filter is in the signal path and the low noise amplifier isbypassed.
 7. The mobile device of claim 6 wherein the plurality of modesfurther includes a fourth mode in which the low noise amplifier is inthe signal path and the blocker filter is bypassed.
 8. The mobile deviceof claim 1 wherein the transceiver includes a blocker detectorconfigured to detect a blocker signal level of the radio frequencysignal, the transceiver further configured to choose the selected modebased on the detected blocker signal level.
 9. The mobile device ofclaim 1 wherein the transceiver is further configured to change a gainof the low noise amplifier based on the selected mode.
 10. The mobiledevice of claim 1 wherein the transceiver includes an automatic gaincontrol system configured to choose the selected mode.
 11. A front-endsystem for a radio frequency communication device, the front-end systemcomprising: a low noise amplifier; a blocker filter; a plurality ofswitches configured to control connectivity of the blocker filter andthe low noise amplifier in a signal path through the front-end system;and a controller configured to control the plurality of switches tooperate the front-end system in a selected mode chosen from a pluralityof modes, the plurality of modes including a first mode in which theblocker filter is before the low noise amplifier in the signal path, anda second mode in which the low noise amplifier is before the blockerfilter in the signal path.
 12. The front-end system of claim 11 whereinthe plurality of switches includes a first crosspoint switch and asecond crosspoint switch, the low noise amplifier electrically connectedbetween a first output of the first crosspoint switch and a first inputof the second crosspoint switch, and the blocker filter connectedbetween a second output of the first crosspoint switch and a secondinput of the second crosspoint switch.
 13. The front-end system of claim12 wherein an output of the second crosspoint switch is coupled to aninput of the first crosspoint switch by a loopback path.
 14. Thefront-end system of claim 11 wherein the plurality of switches includesa first switch connected between an output terminal and an output of theblocker filter, a second switch connected between the output terminaland an output of the low noise amplifier, and a third switch connectedbetween the output terminal and an input terminal.
 15. The front-endsystem of claim 14 wherein the plurality of switches further includes afourth switch connected between the input terminal and an input to thelow noise amplifier, a fifth switch connected between the input terminaland an input to the blocker filter, a sixth switched connected betweenthe output of the low noise amplifier and the input to the blockerfilter, and a seventh switch connected between the input of the lownoise amplifier and the output of the blocker filter.
 16. The front-endsystem of claim 11 wherein the plurality of modes further includes athird mode in which the blocker filter is in the signal path and the lownoise amplifier is bypassed.
 17. The front-end system of claim 16wherein the plurality of modes further includes a fourth mode in whichthe low noise amplifier is in the signal path and the blocker filter isbypassed.
 18. A method of processing received signals in a mobiledevice, the method comprising: receiving a radio frequency signal usingan antenna; processing the received signal using a signal path through afront-end system, the front-end system including a blocker filter, a lownoise amplifier, and a plurality of switches; controlling the pluralityof switches to operate the front-end system in a first mode in which theblocker filter is before the low noise amplifier in the signal path; andcontrolling the plurality of switches to operate the front-end system ina second mode in which the low noise amplifier is before the blockerfilter in the signal path.
 19. The method of claim 18 further comprisingcontrolling the plurality of switches to operate the front-end system ina third mode in which the blocker filter is in the signal path and thelow noise amplifier is bypassed.
 20. The method of claim 19 furthercomprising controlling the plurality of switches to operate thefront-end system in a fourth mode in which the low noise amplifier is inthe signal path and the blocker filter is bypassed.